Shear Bolts

   #1  

treefarmerguy

Bronze Member
Joined
Jan 28, 2012
Messages
69
Tractor
Kubota 5030
I can't find shear bolts for a Puma 74 inch rear mount snow blower. Owner's manual calls for a Grade #2 for the auger. Can I use a regular grad#2 bolt of the same size? The drive shaft calls for a M6 x 40mm bolt with no grade# indicated. Any suggestions appreciated.
 
   #2  

George2615

Super Member
Joined
Feb 28, 2005
Messages
8,675
Location
Central Square, NY
Tractor
LS XR3037HC
Yes, you can use any grade 2 bolt of the same size. Check your local Tractor Supply Store or whatever hardware store near you that carries M6 x 40mm bolts. A standard bolt is a different diameter and if substituted will cause it to shear prematurely. Buy extras when you get them.
 
   #3  

jaydee325

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May 21, 2013
Messages
1,012
Location
Casco, Mi
Tractor
John Deere X584 Garden Tractor & LS R3039H
Metric equivalent to an SAE Grade 2 is a 4.8.

Metric fastener strengths are named property Class and not grade. Even so, the Property Classes are roughly equivalent to the SAE Grade system. The following provides some examples.

Metric Grades
Property Class*****************SAE Grade
4.6****************************Grade 1
4.8****************************Grade 1
4.8****************************Grade 2
8.8****************************Grade 5
9.8**************************9% Stronger
10.9***************************Grade 8
11.9***************************NONE
12.9***************************ASTM A574


The easiest way to tell a metric fastener Property Classis by looking at the fastener for a numeric designation. These decimal numbers will be marked on the hex head or on the top or side of a socket head fastener.
 
   #4  

RickB

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Sep 18, 2000
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14,599
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Up the road from Dollar General WNC
Tractor
Just a Scag
I can't find shear bolts for a Puma 74 inch rear mount snow blower. Owner's manual calls for a Grade #2 for the auger. Can I use a regular grad#2 bolt of the same size? The drive shaft calls for a M6 x 40mm bolt with no grade# indicated. Any suggestions appreciated.

The auger drive uses a common grade 2 bolt as the shear bolt. No relief cuts or fracture points, just a regular hardware store bolt with no marks on the head. The PTO drive shearbolt s a 6x40MM 8.8 hardness. That is a typical good quality metric bolt and will be marked 8.8 on the head. Just about any source of metric hardware will have that size in 8.8 hardness.
 
 
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